Abstract: Using recent results in the field of quantum chaos we derive explicitexpressions for the time scale of decoherence induced by the system-environmententanglement. For a generic system-environment interaction and for a genericquantum chaotic system as environment, conditions are derived for energyeigenstates to be preferred states in the weak coupling regime. A simple modelis introduced to numerically confirm our predictions. The results presentedhere may also help understanding the dynamics of quantum entanglementgeneration in chaotic quantum systems.